1. Field of the Invention
The present invention relates to drug discovery methods, more specifically to NMR methods for identifying atoms of interest in enzyme ligands for generating and screening combinatorial libraries of bi-ligand drug candidates.
2. Background Information
Widespread and sometimes indiscriminate use of antibiotics has allowed certain strains of disease-causing bacteria to become resistant to commonly available antibiotics. As a result, the need for more effective antimicrobial drugs is becoming more pressing. One approach to developing such drugs is to find compounds that bind to essential enzymes in bacteria. When such enzymes have two adjacent binding sites, it is especially useful to find "bi-ligand" drugs that can bind at both sites simultaneously. Such drugs are likely to bind extremely tightly, inactivating the enzyme and ultimately killing the bacteria.
The rapid discovery and development of bi-ligand drugs has been difficult. Bi-ligand drug candidates have been identified using rational drug design, but previous methods are time-consuming and require a precise knowledge of structural features. When searching for a drug that binds to an enzyme at two binding sites, it would be particularly useful to understand how a ligand binds to the enzyme. Specifically, which atoms in the ligand interact with which portions of the enzyme's binding sites?
Recent advances in nuclear magnetic spectroscopy (NMR) have allowed the determination of the three-dimensional interactions between a ligand and an enzyme in a few instances. However, these efforts have been limited by the size of the enzyme and can take years to map and analyze the complete structure of the complexes of enzyme and ligand.
Thus, there is a need to more rapidly identify which atoms in the ligand interact with which portions of the enzyme binding sites so that focused combinatorial libraries can be generated and screened for more effective drugs. The present invention satisfies this need and provides related advantages as well.